Systems for removing lubricants from superplastic-forming or hot-forming dies

ABSTRACT

A method of cleaning a die having an oxide layer is provided. The method includes discharging electromagnetic energy towards a working surface of the die having a layer of at least one of graphite and boron nitride thereon. The electromagnetic energy is discharged at a power output between about 6 kW and about 15 kW such that the layer of at least one of graphite and boron nitride is ablated, and such that the layer is removed without removing an oxide layer between the surface of the die and the layer.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part and claims priority to U.S.patent application Ser. No. 13/732,692 filed Jan. 2, 2013 for “METHODSAND SYSTEMS FOR REMOVING LUBRICANTS FROM SUPERPLASTIC-FORMING ORHOT-FORMING DIES”, which is hereby incorporated by reference in itsentirety.

FIELD

The field of the disclosure relates generally to cleaning manufacturingdies, and more specifically, to methods and systems for removinglubricants from superplastic-forming or hot-forming manufacturing dies.

BACKGROUND

Forming methods for metal components include superplastic forming andhot forming of components. Typically, a metal die, such as a stainlesssteel die, is first treated such that an oxide layer, e.g., a nickeloxide layer, is formed on its working surface. A lubricant is sprayed onor otherwise applied over the oxide layer of the die. The metal die isthen heated, either alone or together with the metal to be formed, andonce the desired temperature is achieved, the metal is formed againstthe die, e.g., using a compressed gas, to form the component. After anumber of components have been formed, the lubricant becomes baked ontothe die, and must occasionally be removed and reapplied, whilepreserving the oxide layer underneath, before additional components maybe formed with the die.

Typically, the baked-on lubricant is removed manually. The operator usese.g. a pneumatic rotary tool and an abrasive pad to grind away thebaked-on lubricant. However, this cleaning process is tedious, timeconsuming, and may remove or disrupt the beneficial oxide layer on theworking surface of the die.

FIG. 1 is a schematic diagram of a component-forming system 100. Thecomponent-forming system 100 includes a die 102, a lower platen 104, anupper platen 106, and a gas inlet 108. The component-forming system 100may be a superplastic-forming system or a hot-forming system.

The die 102 is fabricated from a rigid, temperature-resistant material.In embodiments, the die 102 is a superplastic forming die or ahot-forming die. The die 102 includes a working surface 110 that isshaped to provide a component to be formed therein with a desiredprofile. The working surface 110 includes one or more raised or indentedportions, configured to provide the shape of the component to be formedtherein.

The working surface 110 is coated with an oxide layer 101 for wearresistance and to prevent the formed part from sticking to the diesurface, for example as shown in the enlarged section view of FIG. 1.The system 100 may include a top cover 112 that seals against the die102 at a seal bead 114. In one example, the seal bead 114 includes aseal or gasket for improved sealing of the top cover 112 to the die 102.In another example, the seal bead 114 is formed on the die 102 and thecover is sealed to the die using an adhesive, mechanical means, such asa clamp, or other sealing devices such as a hydraulic press that allowthe component forming system to function as described herein. When thetop cover 112 is sealed to the die 102, a forming chamber 116 is definedas a space between the top cover 112 and die working surface 110.

The gas inlet 108, formed for example in the top cover 112, is in flowcommunication with the forming chamber 116. A supply of pressurized gas(not shown) is provided to the forming chamber 116 through the gas inlet108 to apply a pressure within the forming chamber 116. A gas discharge118 is in flow communication with the forming chamber 116, and allowsgas supplied via the inlet 108 to exit the forming chamber 116.

In operation, the die 102 is first coated with a lubricant 103, such asgraphite and/or boron nitride. As used herein, lubricant 103 refers tolubricants that are not paints. Typically, the lubricants are sprayedonto the working surface 110 of the die 102 to form a substantiallyuniform layer of lubricant 103. However, other methods of applying thelubricant 103 may be used, such as wiping, dipping, rolling and thelike. After the lubricant 103 has been applied to the die, a materialstock 120 is placed into die 102. Material stock 120 may be a metal orplastic material to be formed, such as titanium, aluminum, nickel, othermetals and metal alloys or combinations thereof The top cover 112 isclosed and the die 102 is heated by a heater (not shown). The die 102 isheated until the material stock 120 reaches a predetermined temperatureof approximately between 850 degrees to 1800 degrees Fahrenheit (454° C.to 983° C.), depending on the forming process and material being formed.The die 102 and the cover 112 are placed between the lower platen 104and the upper platen 106 and a pressure is applied to one or both of theplatens.

The heated material stock 120 is then biased against the working surface110 by pressure exerted by the pressurized gas supplied through theinlet 108. The pressure is applied to the material stock 120 until thematerial stock takes the shape of the working surface 110, and acomponent 122 is formed. The formed component 122 is then removed fromthe die 102. The above described forming procedure may be performed oneor more times before spent lubricant is removed and new lubricant isapplied to the die. Alternatively, it may be necessary to remove oldlubricant 103 and apply a new layer of lubricant to the die 102 aftereach component 122 is formed and removed from the die.

SUMMARY

Accordingly, it is desirable to provide an improved method and apparatusfor removing a lubricant from a forming die.

In one aspect, a method of cleaning a die having an oxide layer isprovided. The method includes discharging electromagnetic energy towardsa working surface of the die having a layer of at least one of graphiteand boron nitride thereon. The electromagnetic energy is discharged at apower output between about 6 kW and about 15 kW such that the layer ofat least one of graphite and boron nitride is ablated, and such that thelayer is removed without removing an oxide layer between the surface ofthe die and the layer.

In another aspect, a method of cleaning a die is provided. The methodincludes analyzing a working surface of the die with an analyzing deviceto determine a thickness of a layer of at least one of graphite andboron nitride thereon, and based on the thickness of the layer,discharging electromagnetic energy from an electromagnetic-energyemission device (EEED) to irradiate the surface of the die with theelectromagnetic energy. The electromagnetic energy is discharged at apower output between about 6 kW and about 15 kW such that the layer ofat least one of graphite and boron nitride is ablated, and such that theelectromagnetic energy removes the layer without removing an oxide layerbetween said working surface and said layer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a component forming die.

FIG. 2 schematically shows an exemplary optical cleaning system for aforming die.

DETAILED DESCRIPTION

After the component 122 has been removed from the die 102, the die 102may be cooled to room temperature and cleaned using an exemplarycleaning system 200 best shown in FIG. 2. In one example, the die 102 isplaced onto a holder 202 that supports the die 102 during the cleaningoperation. The holder 202 may include a device configured for rotationaland/or translational movement, which allows the die 102 to move, rotateand/or translate with respect to one or more other components ofcleaning system 200. For example, in one embodiment, the holder 202moves the die with respect to a beam of electromagnetic energy emittedfrom the emission device (EEED) 204. In one aspect, the holder 202 isalso configured to align the die 102 with respect to one or more othercomponents of the cleaning system 200.

The cleaning system 200 includes an electromagnetic-energy emissiondevice (EEED) 204, such as a laser having a power output of betweenabout 8 kilowatts (kW) to about 15 kW. In one embodiment, the EEED 204is a fiber laser, such as a 15 kw fiber laser manufactured by IPG(Oxford, Mass.) or Fraunhofer (Munich, Germany). In other embodiments,the EEED 204 may be any electromagnetic-energy emission device capableof functioning as described herein. The EEED 204 is configured to emit abeam 208 of electromagnetic energy capable of ablating a lubricant 103from a surface of the die 102, as discussed further herein. Suitablelubricants include graphite and Boron Nitride or the like. In oneembodiment, the EEED 204 is coupled to a movable arm 206 that provides amovement, or steering capability to direct the beam 208 in a desireddirection toward die 102. In some variants, the EEED outputs betweenabout 12 kW and about 15 kW of power.

In one example, a scanning device 216, which may also be referred toherein as a scanner, is provided to enable direction and/or distribution(e.g., spreading and/or focusing) of the beam 208 onto the die 102. Thescanning device 216 may be a reflective device capable of reflecting ordirecting the beam 208 onto a surface of the die 102, such as a mirror.In one such embodiment, the scanning device 216 is a faceted rotatingmirror, such as a scanner manufactured by EWI® (Columbus, Ohio). Inother embodiments, scanning device 216 is an oscillating reflectivesurface having a flat or contoured shape. In some variants, the scanningdevice 216 has a parabolic shape for concentrating the electromagneticenergy. In yet another embodiment, scanning device 216 may be controlledor otherwise adjusted by adjusting device 218 to control parameters suchas raster speed, laser spot size and laser energy density. In onealternative, the scanning device 216 may be omitted, with EEED 204emitting the beam 208 directly onto the die 102.

In one example, an effluent-capture device 214 is provided proximate thescanning device 216 or die 102. The effluent-capture device 214 may be avacuum device, or other device capable of capturing effluents generatedduring the cleaning operation of the die 102. Such effluents may includevaporized particles of lubricant 103 that have been ablated from theworking surface 110 of the die 102. The effluent-capture device 214 maybe connected to a vacuum source 220 by a conduit 222. In some aspects,the conduit 222 is flexible, and allows the effluent-capture device 214to be moved along die 102 in the vicinity of the cleaning operation. Insome variants, effluent-capture device 214 is coupled to a movable arm,such as a robotic arm or the like, for moving the effluent-capturedevice with respect to the die 102.

One or more of EEED 204, scanning device 216 and effluent-capture device214 are connected to a controller 210, such as a computer systemincluding a processor (not shown). The processor is generally any pieceof hardware that is capable of processing information such as, forexample, data, computer-readable program code, instructions or the like(generally “computer programs,” e.g., software, firmware, etc.), and/orother suitable electronic information. More particularly, for example,the processor may be configured to execute computer programs, which maybe stored onboard the processor or otherwise stored in a memory (notshown). The processor may be a number of processors, a multi-processorcore or some other type of processor, depending on the particularimplementation. Further, the processor may be implemented using a numberof heterogeneous processor apparatuses in which a main processor ispresent with one or more secondary processors on a single chip. Asanother illustrative example, the processor may be a symmetricmulti-processor apparatus containing multiple processors of the sametype. In yet another example, the processor may be embodied as orotherwise include one or more application-specific integrated circuits(ASICs), field-programmable gate arrays (FPGAs) or the like. Thus,although the processor may be capable of executing a computer program toperform one or more functions, the processor of various examples may becapable of performing one or more functions without the aid of acomputer program.

The memory is generally any piece of hardware that is capable of storinginformation such as, for example, data, computer programs and/or othersuitable information either on a temporary basis and/or a permanentbasis. In one example, the memory may be configured to store variousinformation in one or more databases. The memory may include volatileand/or non-volatile memory, and may be fixed or removable. Examples ofsuitable memory include random access memory (RAM), read-only memory(ROM), a hard drive, a flash memory, a thumb drive, a removable computerdiskette, an optical disk, a magnetic tape or some combination of theabove. Optical disks may include compact disk read-only-memory (CD-ROM),compact disk read/write memory (CD-R/W), digital video disk memory(DVD), or the like. In various instances, the memory may be referred toas a computer-readable storage medium which, as a non-transitory devicecapable of storing information, may be distinguishable fromcomputer-readable transmission media such as electronic transitorysignals capable of carrying information from one location to another.Computer-readable medium, as described herein, may generally refer to acomputer-readable storage medium or computer-readable transmissionmedium.

In addition to the memory, the processor may also, but need not be,connected to one or more interfaces for displaying, transmitting and/orreceiving information. These interfaces may include one or morecommunications interfaces (none shown) and/or one or more userinterfaces. The communications interface may be configured to transmitand/or receive information, such as to and/or from other apparatus(es),network(s) or the like. The communications interface may be configuredto transmit and/or receive information by physical (by wire) and/orwireless communications links. Examples of suitable communicationinterfaces include a network interface controller (NIC), wireless NIC(WNIC) or the like.

The user interfaces may include a display and/or one or more user inputinterfaces. The display may be configured to present or otherwisedisplay information to a user, suitable examples of which include aliquid crystal display (LCD), light-emitting diode display (LED), plasmadisplay panel (PDP) or the like. The user input interfaces may be bywire or wireless transmission, and may be configured to receiveinformation from a user, such as for processing, storage, and/ordisplay. Suitable examples of user input interfaces include amicrophone, image or video capture device, keyboard or keypad, joystick,touch-sensitive surface (separate from or integrated into a touchscreen), biometric sensor or the like. The user interfaces may furtherinclude one or more interfaces for communicating with peripherals suchas printers, scanners or the like.

As indicated above, program code instructions may be stored in memory,and executed by a processor, to implement functions of the system,apparatuses and their respective elements described herein. As will beappreciated, any suitable program code instructions may be loaded onto acomputer or other programmable apparatus, e.g., from a computer-readablestorage medium to produce a particular machine, such that the particularmachine becomes a means for implementing the functions specified herein.These program code instructions may also be stored in acomputer-readable storage medium that can direct a computer, a processoror other programmable apparatus to function in a particular manner tothereby generate a particular machine or particular article ofmanufacture. The instructions stored in the computer-readable storagemedium may produce an article of manufacture, where the article ofmanufacture becomes a means for implementing functions described herein.The program code instructions may be retrieved from a computer-readablestorage medium and loaded into a computer, processor or otherprogrammable apparatus to configure the computer, processor or otherprogrammable apparatus to execute operations to be performed on or bythe computer, processor or other programmable apparatus.

The controller 210 may be operatively coupled to each of the devices bya wired or wireless connection that provides one-way or two-way datatransfer between the controller and the devices. In one example, thecontroller 210 includes an input device 212, such as a keyboard or thelike, that allows an operator to input, adjust, or otherwise regulatethe operating parameters of the devices connected to the controller.Such operating parameters may include one or more of a laser power,speed, direction of motion, angle of attack, speed ofrotation/oscillation of scanning device 216, suction control andlocation of effluent-capture device 214. For example, in one aspect, thecontroller 210 is configured with a set of options selectable based uponthe size and material of the die and the specific coating to be removed.The available options include one or more predetermined operatingparameters for effectively cleaning lubricant 103 from the die 102without removing or disrupting the oxide coating of the die 102. Suchpredetermined options may be based on one or more of the lubricant 103to be removed, the power of the EEED, the material of die 102, thethickness of the lubricant 103, the type and/or thickness of the oxidecoating, or other user-determined parameters.

During a cleaning operation, the EEED 204 emits the beam 208, which isdirected onto the surface of the die 102 to be cleaned of a lubricant103. It is to be noted that the energy of the beam 208 and the speed atwhich it travels across the surface of the die 102 determines, at leastin part, the extent to which lubricant 103 is removed from the surfaceof die 102. In one example, the travel speed of the beam 208 across thesurface of die 102 is controllable to be between about 25 millimetersper second to about 200 millimeters per second, or other speeds whichenable the lubricant 103 cleaning device to function as describedherein. The travel of the beam 208 across the surface of die 102 may becontrolled by the movement of arm 206, rotation and/or translation ofthe scanning device 216, and/or by movement of the die holder 202. Forexample, when using high power output (e.g., about 10 kW to about 15kW), the beam 208 may be moved more quickly (e.g., about 125 mm/sec toabout 200 mm/sec or greater) across the surface of the die 102 to removethe lubricant 103. Other factors, such as the type of the lubricant 103,and thickness of the lubricant 103 may also affect the rate of removalof lubricant 103 during cleaning. The thickness of the lubricant 103 maybe constant, or vary along the surface of die 102. In one example, thethickness of the lubricant 103 may be between about 0.005 to about 0.020inches. In other variants, the lubricant 103 layer may have otherthicknesses. Thus, the operator or controller 210 may adjust theoperating parameters of the cleaning system to vary the amount oflubricant 103 removed, or the rate at which the lubricant 103 isremoved. In one embodiment, scanning device 216 is controlled to provideoverlap of the beam 208 with a portion of the working surface that hasbeen previously irradiated by beam 208.

In one example, a layer 226 of gloss black paint is applied overlubricant 103 and onto the surface of die 102. It is believed, withoutbeing bound by any particular theory, that layer 226 of gloss blackpaint facilitates absorbing the energy of beam 108, and more effectivelytransfers the energy to lubricant 103 to enhance the ablation oflubricant 103 from die 102. In operation, layer 226 of gloss black paintis applied over lubricant 103 and allowed to dry and/or cure prior todirecting beam 108 onto the surface of die 102. Layer 226 has anythickness that enables cleaning system 200 to function as describedherein. In one example, layer 226 has a thickness defined within a rangebetween about 0.5 mils and about 5 mils.

The beam 208 is configured to have the correct wavelength and sufficientenergy to vaporize or otherwise ablate the lubricant 103 from theworking surface of the die 102 without disrupting the oxide coating ofthe die 102, when the beam contacts the lubricant 103 as it traversesthe working surface of the die.

In one example, the cleaning system 200 is configured to automaticallyanalyze the surface of the die 102 to determine portions of the surfacethat require cleaning, such as by measuring a thickness and/ordetermining a location of the lubricant 103 thereon. The analysis of thesurface may be performed by a analyzing device 224 that is operablyconnected to the controller 210. During analysis, the working surface ofthe die to be analyzed faces the analyzing device 224. The analyzingdevice 224 may be an optical, sonic or mechanical analyzing devicecapable of analyzing the surface of die 102. For example, the analyzingdevice 224 may be a spectroscopic or ultrasonic coating thicknessmeasurement device, such as a Positector® manufactured by DeFelsko ofNY, USA or the like. In another embodiment, analyzing device 224 is abarcode reader or the like configured to identify the die 102 (e.g., bya tool number), such as by reading a barcode or the like, to call uppre-programmed cleaning routines and to locate the die 102 relative tothe cleaning system 200.

In one example, the scan of the surface of die 102 is performed beforethe cleaning operation takes place to determine which locations on theworking surface of the die 102 require cleaning. In another example, thescan of the surface is conducted after all or a part of the cleaningoperation has taken place, to determine whether the beam 208 hassufficiently removed the lubricant 103, or whether at least oneadditional cleaning pass of the beam 208 over the working surface, or aportion thereof, of the die 102 is required to remove any remaininglubricant 103. In one alternative, the scan of the working surface ofthe die 102 may be performed simultaneously with the cleaning operation.The controller 210 may adjust one or more of the operating parameters,discussed above, for effective cleaning of the lubricant 103 from thedie 102 based on the data gathered using any of the previously describedscanning methodologies. Accordingly, it will be appreciated thatadjustment of one or more of the operating parameters of the cleaningsystem 200 by the controller 210 may take place either a discrete periodof time after or concurrently with the cleaning step. For example, ifthe scan data, gathered as the cleaning operation progresses, indicatesthat lubricant 103 is only being partially removed from the workingsurface of the die, the controller 210 may, responsive to this feedback,instantaneously increase the power output of the EEED 204 and/ordecrease the travel speed of the beam 208 to ensure optimum removal ofthe lubricant 103 from the working surface of the die 102. Conversely,responsive to the scanned data, the controller 210 may, for example,instantaneously decrease the power output of the EEED 204 and/orincrease the travel speed of the beam 208 to avoid damaging the oxidelayer 101. In view of the foregoing, those skilled in the art willappreciate that any number of operating parameters of the cleaningsystem 200 may be adjusted in a variety of ways based on the scan datareceived by the controller 210 from the analyzing device 224.

In one example, the die 102 is a die for forming a component of anaircraft, automobile, locomotive or the like. In other embodiments, thedie 102 is a general tooling die or the like.

In one example, a plurality of components of the cleaning system 200 arecontained in a fully integrated unit. In one aspect, the fullyintegrated unit includes at least the EEED 204, the scanning device 216,arm 206, die holder 202, and the effluent-capture device 214. Anenclosure (not shown) may house the components of the fully integratedunit.

Exemplary embodiments of the systems, methods, and an apparatus forcleaning a lubricant 103 from forming dies are described above indetail. The systems, methods, and apparatus are not limited to thespecific embodiments described herein, but rather, components of thesystems and apparatus, and/or steps of the methods may be utilizedindependently and separately from other components and/or stepsdescribed herein. For example, the methods may also be used incombination with other cleaning and forming systems, methods, andapparatuses, and are not limited to practice with only the systems,methods, and apparatus as described herein. Rather, the exemplaryembodiment can be implemented and utilized in connection with many otherapplications.

Although specific features of various embodiments of the disclosure maybe shown in some drawings and not in others, this is for convenienceonly. In accordance with the principles of the disclosure, any featureof a drawing may be referenced and/or claimed in combination with anyfeature of any other drawing.

This written description uses examples to disclose the invention,including the best mode, and also to enable any person skilled in theart to practice the invention, including making and using any devices orsystems and performing any incorporated methods. The patentable scope ofthe invention is defined by the claims, and may include other examplesthat occur to those skilled in the art. Such other examples are intendedto be within the scope of the claims if they have structural elementsthat do not differ from the literal language of the claims, or if theyinclude equivalent structural elements with insubstantial differencesfrom the literal languages of the claims.

What is claimed is:
 1. A method of cleaning a die having an oxide layer,the method comprising: discharging electromagnetic energy towards aworking surface of the die having a layer of at least one of graphiteand boron nitride thereon, wherein the electromagnetic energy isdischarged at a power output between about 6 kW and about 15 kW suchthat the layer of at least one of graphite and boron nitride is ablated,and such that the layer is removed without removing an oxide layerbetween the surface of the die and the layer.
 2. A method according toclaim 1, wherein the electromagnetic energy comprises a laser beam.
 3. Amethod according to claim 2, further comprising moving the laser beamacross the working surface at a speed between about 25 millimeters persecond and about 200 millimeters per second.
 4. A method according toclaim 1, further comprising capturing an effluent generated whenremoving the layer.
 5. A method according to claim 4, wherein theeffluent is captured with a suction device.
 6. A method according toclaim 1, wherein discharging electromagnetic energy comprisesdischarging electromagnetic energy consistent with a set of operatingparameters for an electromagnetic-energy emission device (EEED) thatincludes at least one of a wavelength and power level of theelectromagnetic energy, a speed at which a beam of the electromagneticenergy traverses the working surface, a speed at which the die is movedwith respect to a beam of the electromagnetic energy, and a number oftimes the beam of the electromagnetic energy traverses the workingsurface along at least a portion of a previously traversed path.
 7. Amethod according to claim 6, further comprising analyzing the workingsurface during or after exposing the working surface to theelectromagnetic energy and detecting how much of the layer remains onthe working surface.
 8. A method according to claim 7, furthercomprising modifying the set of operating parameters based on how muchof the layer remains on the working surface.
 9. A method according toclaim 1, further comprising: applying a layer of gloss black paint overthe layer of at least one of graphite and boron nitride; and dischargingthe electromagnetic energy towards the working surface of the die havingthe layer of at least one of graphite and boron nitride and the layer ofgloss black paint thereon.
 10. A method of cleaning a die, the methodcomprising: analyzing a working surface of the die with an analyzingdevice to determine a thickness of a layer of at least one of graphiteand boron nitride thereon; and based on the thickness of the layer,discharging electromagnetic energy from an electromagnetic-energyemission device (EEED) to irradiate the surface of the die with theelectromagnetic energy, wherein the electromagnetic energy is dischargedat a power output between about 6 kW and about 15 kW such that the layerof at least one of graphite and boron nitride is ablated, and such thatthe electromagnetic energy removes the layer without removing an oxidelayer between said working surface and said layer.
 11. A methodaccording to claim 10, further comprising performing an identificationof the die using the analyzing device.
 12. A method according to claim11, further comprising controlling operating parameters of the EEEDusing a preprogrammed cleaning routine based upon the identification ofthe die.
 13. A method according to claim 11, further comprisingmodifying operating parameters of the electromagnetic-energy emissiondevice (EEED) based on said identification of the die, said operatingparameters including at least one of a wavelength of the electromagneticenergy, a power level of the electromagnetic energy, a speed at which abeam of the electromagnetic energy traverses the working surface, aspeed at which the die is moved relative to the beam of theelectromagnetic energy, and a number of times the beam traverses theworking surface along at least a portion of a previously traversed path.14. A method according to claim 10, wherein said electromagnetic energyis a laser beam.
 15. A method according to claim 14, further comprisingmoving the laser beam across the working surface at a speed betweenabout 25 millimeters per second and about 200 millimeters per second.16. A method according to claim 10 further comprising capturing aneffluent generated when removing the layer.
 17. A method according toclaim 16, wherein the effluent is captured with a suction device.
 18. Amethod according to claim 1, further comprising: applying a layer ofgloss black paint over the layer of at least one of graphite and boronnitride; and discharging the electromagnetic energy towards the workingsurface of the die having the layer of at least one of graphite andboron nitride and the layer of gloss black paint thereon.